Blue Bonnet: breakaway stack of buckets

My original plan was to do a build thread, but the calendar got away from me and I finished this one last night just ahead of today's Moffett launch. I'm too tired to do a proper write-up tonight, so I'm just posting pictures. I plan to add explanatory text tomorrow or Monday.

The inspiration for this project is, in large part, Kevin's L3 ship: https://www.rocketryforum.com/showthread.php?21740-Buckets-v2

Ari.

G78G

ObOpenRocket

Was the idea to have the six buckets act as parachutes and slow the decent? It didn't seem to work too well. Any ideas how to make it work better?

But of course it did. What makes you think it didn't?

Works about as well as this one: https://www.rocketryforum.com/showthread.php?40716-Breakaway-2-6-quot-upscale-build-The-Castaway

A larger version would need a parachute for the main event, but this one gets away with just the buckets.

Ari.

So, the buckets are stacked together and blow apart at ejection? Interesting. I wish I'd been able to make it out to Saturday's Moffett launch.

The weather was miserable on Saturday Robert, you missed little. And I'm coming round to your point of view about flying on concrete. Concrete is nasty to rockets in general, and on a cold day it is especially nasty to plastic when it freezes and becomes brittle. There are cracks in the top and bottom buckets. The good news is that replacing them is easy. They are almost literally a dime a bucket (well--accounting for inflation; they are actually closer to $2 but still easy to replace).

The general idea is exactly as you say it. It's like one of my breakaways but with plastic buckets for sections.

Ari.

iter said:

But of course it did. What makes you think it didn't?
Ari.

Click to expand...

The three pics you posted all show the fin can following the buckets down ballistic. Was the fin can the big drag and held back the buckets? If that is the case, the buckets didn't act as a series of parachutes as I assumed you were trying to do. I expected the fin can to be the first down with the buckets following.

Oh, I see what you mean. All the weight is in the nose to get the CG right. Last thing I want is a rocket with experimental recovery and marginal stability. So on the way down, the fin can ends up with a lower area loading. If I'd left the weight on the fin can and popped the buckets with just their weight, it might very well land the other way, with the fin can at the bottom.

As it stands, the buckets all flop around a fair bit. You can see the fin can top in the one-before-last photo, and one of the other buckets on top in the landing image. The last image probably is indicative of the relative area loading: nose weight is pulling one end of the train down, (lighter) tail weight is pulling the other end down, and the buckets in the middle produce drag. The middle image is with me standing almost directly under the flight path--the train is more horizontal than vertical at that point. Featureless overcast sky complicates orientation.

Ari.

Handeman said:

The three pics you posted all show the fin can following the buckets down ballistic. Was the fin can the big drag and held back the buckets? If that is the case, the buckets didn't act as a series of parachutes as I assumed you were trying to do. I expected the fin can to be the first down with the buckets following.

Click to expand...

I think the bucket design is pretty cool!
Just to clarify, the Odd'l Rockets Break-Away is balanced and actually falls horizontally.
It took a lot of test flights and prototypes to get it to fall horizontal.

Thank you for your encouragement Hans! Breakaway is my daughter Leah's favorite rocket. She likes painting more than any other part of building a rocket, and a multi-color job like this is a delight for her.

Maybe you can talk more about your development process with Breakaway. (The non-standard tubing size in particular is a source of surprise for me. On my Breakaway's first flight, the top-most section separates and we lose it. My initial reaction is "we can make a new one as soon as we get home, I have enough BT-50 tubing around." But the couples seems to be about BT-50 size and the body sections are wider than that.)

Ari.

The tubing used is an old Centuri size, ST-10. Dimensions: ID: 1.00", OD: 1.04", WT: 0.020". Advantages: Sturdier than BT-50. Disadvantages: Fewer suppliers (Semroc or Balsa Machining Service (BMS)), doesn't fit 24mm motors very snugly. I noticed by looking at the Odd'l Rockets site that most of his kits appear to use Centuri sized tubes.

For LPR there are three major body tube sizing systems, Estes (BT-series, look it up on the chart), Centuri (ST-series, series number is the ID of the tube in tenths of an inch, i.e. ST-7: ID: 0.715", OD: 0.759")), and MRI/MPC/AVI/Quest (T-series, number is OD in millimeters, i.e. T-20: OD: 20mm (0.787")). Hope this helps.

I'll add making one of these to my "bucket list..."